Jet pipe regulator with null position adjustment



3mm E. h. FARNAN, JR. ETAL 3324,71

JET PIPE REGULATOR WITH NULL POSITION ADJUSTMENT Filed April 5, 1965FIGE.

FIG. 2.

ENVENTOWS.

EDWARD H. FARNAi, JR. ROBERT EKAY United States Patent 3,324,871 JETPIPE REGULATQR WITH NULL POSITION ADJUSTMENT Edward H. lFarnan, Jr.,Arlington Heights, 111., and

Robert E. Kay, Birmingham, Mich., assiguors to Sperry Rand Corporation,Troy, Mich., a corporation of Delaware Filed Apr. 5, 1965, Ser. No.445,624 12 Claims. (Cl. 137-83) This invention relates to powertransmissions and is particularly applicable to those of the typecomprising two or more fluid pressure energy translating devices, one ofwhich may function as a pump and another as a fluid motor.

The invention is more particularly concerned with electro-hydraulic jetpipe control systems. In systems of this type, the first stage of thesystem comprises a jet pipe having a nozzle at one end through which ahigh velocity fluid jet issues toward two closely spaced receiver portsleading or connected to output ports of the first stage. The outputports of the first stage may be directly connected to an output membersuch as an actuating cylinder or to a second stage fluid pressureactuated directional control valve.

If the jet pipe nozzle is acurately positioned or centered over the tworeceiver ports, no differential pressure is created at the output portsof the first stage when the jet pipe is in what is known as the nullposition as the two receiver ports are adapted in the null position ofthe jet pipe to receive an equal amount of fluid so as to create apressure balance. The jet pipe may be pivoted, swung, or flexed by atorqueor force motor in response to signals communicated thereto forshifting the jet pipe, thus shifting the nozzle more or less over one ofthe receiver ports in order to create a differential of pressure at theoutput ports of the first stage. Generally, adjustable stops areprovided to limit movement of the jet pipe in opposite directions forpreventing overshifting of the jet pipe and thus loss of communicationof the nozzle with the receiver ports.

In systems of this type, it is essential that the receiver ports becentered as closely as possible relative to the jet pipe nozzle with thejet pipe in the null position as deviations from the centered positionlead to instability and inaccurate response. In order to provide propercentering, it has been necessary, after assembly and after being inservice, to make final or corrective adjustments necessitating the useof gauges and special aligning instruments and tools which istime-consuming and expensive.

It is, therefore, an object of this invention to provide an improvedhydraulic jet pipe control system.

It is another object of this invention to provide a hydraulic jet pipecontrol system having means for automatically centering the receiverports relative to the nozzle in the null position of the jet pipe.

It is still another object of this invention to provide in anelectro-hydraulic jet pipe control system a receiver port member whichis self-centering relative to the jet pipe nozzle and which is thenlocked in the centered position for normal operation of the system.

It is a further object of this invention to provide in a system of thetype aforementioned, a receiver port spool which may be automaticallycentered relative to the jet pipe nozzle in the null position of the jetpipe by pressure fluid from the nozzle delivered through the receherports to balanced end areas of the spool member and then locked in thecentered position.

It is another object of this invention to provide an improvedelectro-hydraulic jet pipe control system having a built-in,self-centering adjusting feature which is simple in construction,economical, and which provides a compact and efiiciently operatingsystem.

Further objects and advantages of the present invention will be apparentfrom the following description, refer ence being had to the accompanydrawing wherein a preferred form of the present invention is clearlyshown.

In the drawing:

FIGURE 1 is a sectional View of an electro-hydraulic jet pipe controlsystem embodying a preferred form of the present invention.

FIGURE 2 is a fragmentary sectional view on an enlarged scale of aportion of the jet pipe control system shown in FIGURE 1.

FIGURE 3 is a top view of the receiver spool shown in FIGURE 2.

FIGURE 4 is a sectional view of the receiver spool taken on line 44 ofFIGURE 3.

Referring now to the drawing and more particularly FIGURES l and 2,there is shown an electro-hydraulic et pipe control system, indicatedgenerally by the numeral I10, comprising a housing 12 within which thereis mounted a first stage force motor 14 for operating a jet pipe 16having a nozzle 18 at one end thereof, which is accurately positioned inthe null position shown over two jet receiver ports 20 and 22 of areceiver spool 24. There is also shown a second stage directionalcontrol valve spool 26 operated by fluid pressure differentialcontrolled by the jet pipe. It should be understood, however, that thesecond stage may comprise a directly actuated output member, such as amotor of the actuating cylinder type. It should also be noted that forpurposes of more clearly illustrating the pro-operation or in service,self-adjusting centering features of the receiver spool positionwiserelative to the jet pipe nozzle, hereinafter described, the receiverspool and jet nozzle end of the jet pipe are shown in FIGURES 2 and 3 asif the complete system shown in FIGURE 1 has been rotatedcounterclockwise.

The jet pipe 16 is provided with an enlarged externally threaded portion28 at the end thereof opposite to the nozzle Which serves to anchor thepipe in one end of a longitudinal bore 30 which extends completelythrough the housing. The force motor 14 comprises a coil 32 surroundinga magnet 34, all of which is protected by a cover 35 fastened to thehousing 12, the coil 32 being clamped at 36 to the jet pipe near thenozzle end thereof for flexing the pipe in the bore 30 in response tosignals imposed through wiring 38 connected to the force motor 14.

The output member of the second stage part of the system comprisingcontrol valve spool 26 is shiftably mounted within a longitudinal bore40 of the housing 14). Bore 40 is provided with an annular pressuresupply port 42 located between two operating or motor ports 44 and 46and two return or tank ports 48 and 59, respectively, equally spaced onopposite sides of the two operating or motor ports 44 and 46. Thecontrol valve spool 26 is provided with centrally located spaced apartland members 52 and 54 and extreme end lands 56 and 58, respectively,having balanced pressure effective end surface areas 57 and 59. Thevalve spool 26 is biased to the position shown closing off communicationbetween all ports by means of spring members 61 and 63, respectively,mounted in fluid pressure end chambers 65 and 67. A differential of,

pressure in the chambers 65 and 67 created by flexing of the jet pipe 16and acting on the balanced spool end areas 57 and 59 is adapted to shiftthe valve spool 26 to conduct a pressure fluid supply source connectedto pressure port 42 to one of the motor ports 44 or 46 while connectingthe remaining motor port to one of the tank ports. Thus, when the spool26 is shifted leftwardly, the pressure port 42 is connected to motorport 44 and motor port 46 is connected to the tank port 50; and when thevalve spool 26 is shifted rightwardly, pressure port 42 is connected tomotor port 46 and the motor port 44 is connected to the tank port 48.

The same pressure fluid supply source connected to the pressure port 42of the second stage control valve 26 is also adapted to be connectedthrough a pressure reducing valve, not shown, to a plurality oftransverse ports 60 at the enlarged end of the first stage jet pipe,which ports are directly connected to the hollow portion of the pipe,indicated by the numeral 61, terminating in the jet nozzle 18.

The receiver spool member 24 is mounted in a bore 62 of the housingwhich extends from that side of the housing in which the force motor ismounted. Bore 62 is perpendicular to and intersects both longitudinalbore 30, in which the jet pipe is mounted, and chamber 65 at one end ofbore 40, in which control valve spool 26 is mounted. A plug 64maintained by a snap ring 66 closes the bore 62.

Referring now to FIGURES 2, 3, and 4, the receiver spool 24 isconstructed with a centrally located cutaway or recessed portion 27 andon two opposing side walls of which are formed ledges or shelves 29 onwhich is fixedly located a thin plate member 68 having a guide slot 70for the jet pipe 16. The slot 70 is accurately positioned over thereceiver ports and 22 which open to a flat surface 31 in the bottom ofthe recessed portion 27. End wall surfaces 72 and 74 of the slot 70limit the movement of the jet pipe in opposite directions so that thejet pipe nozzle 18 is never out of communication with either of thereceiver ports 22 or 20; and thus, when the jet pipe is flexed, the jetstream will always be directed into one or the other of the receiverports. The left receiver port 22, as viewed in FIGURES 2 and 3, extendsangularly into the spool and intersects a cross passage 76 which extendscompletely axially through the spool to the right end thereof, openingto a chamber 78 in which is exposed a receiver spool right end surfacearea 80. The right receiver port 20 extends angularly into the spool ina direction opposite to that of port 22 and intersects a cross passage82 which extends axially completely through the spool to a chamber 84 atthe left end of the spool in which a receiver spool left end pressuresurface area 86, equal in area to that of the right end surface 80, isexposed.

Chamber 84 to which receiver port 20 is connected and which is formed atthe interior end of bore 62 in which the receiver spool 24 is mounted,intersects chamber 65 of bore 40 in which control spool 26 is mounted.Chamber 78 which is formed at the opposite outer end of bore 62 in whichreceiver spool 24 is mounted and to which receiver port 22 leads, isconnected by suitable passages to the end chamber 67 of bore 40 in whichcontrol valve 26 is mounted, only one of said passages being shown andindicated by the numeral 87. Thus, the chambers 78 and 84 serve asoutput ports of the first stage to which the output member of the secondstage is connected. A common return port for the two stages of thesystem adapted to be connected to a reservoir or tank is indicated inFIGURE 1 by the numeral 95.

The nozzle end of the jet pipe 16, at assembly of the control system, isinserted through the slot 70 of the receiver spool 24, the longitudinalaxis of the guide slot 70 being in the same plane as the commoncenterline of the receiver ports and the slot width being sufficient toallow free movement of the jet pipe nozzle along the common axis of thereceiver ports.

During normal operation of the control system, a differential ofpressure on pressure surface areas 80 and 86 of the receiver spool 24 isineffective to shift the spool as the spool 24 is locked in the positionshown by a locking screw 88. The locking screw 88 is threaded into thebore and has a stub end 90 which is fitted into another 4 slot 92 intothe receiver spool 24 opposite the receiver ports 20 and 22. The stubend 90 is located in the slot 92 and contacts a surface 93 of thereceiver spool for locking the receiver spool and which also preventsthe receiver spool from rotating.

The jet pipe 16 which extends through the receiver guide slot 70, issuesa high velocity fluid jet through the nozzle 18 toward the receiverports 20 and 22. The receiver ports are adapted to receive the jetstream and convert its kinetic energy into a differential staticpressure.

After assembly of the control system but before operation or in fieldservice, the receiver spool will be self-adjusting for accuratelypositioning or centering the jet nozzle 18 over the two receiver ports20 and 22 merely by loosening the locking screw 88 to permit slightaxial movement of the receiver spool 24. With the locking screw 88loosened, a source of pressure fluid supply connected to the jet pipeports 60, and with no input signal being applied to the force motor 14,so as to maintain the jet pipe in the bore 30 in the null positionshown, any pressure differential at opposite ends of the receiver spoolcaused by one receiver port getting more fluid than the other will shiftthe receiver spool unitil the receiver ports are accurately centeredabout the jet stream and nozzle 18. The differential pressure inchambers 78 and 84 at opposite ends of the receiver spool bore 62 actingon receiver spool end surface areas and 86 causes the receiver spool 24to move or shift until a pressure balance exists between both receiverports and their respective correlated chambers to which they areconnected. This pressure balance will only be created when the nozzle 18is accurately centered or positioned over the receiver ports. Thisbalance is reached almost immediately, and when achieved, the lockingscrew 88 is tightened to impose the stub end on the receiver spoolsurface 93, thus accurately fixing or locking the receiver spoolposition for normal operation of the control mechanism. The receiverguide slot 70 serves to keep the jet pipe (and jet stream) on the commonaxis of the receiver ports and to limit its travel to the position ofmaximum pressure recovery. No gauges, special tools or instruments, ordisassembly of the system are required to provide proper centering ofthe receiver ports relative to the nozzle.

Upon operation of the force motor and with the receiver spool in thelocked position, .the jet pipe is flexed and the differential pressurecaused by directing the jet stream into one or the other of the receiverports is used to control the movement of the directional valve spool 26or may be used to directly actuate a second stage output member otherthan control valve spool 26.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all com ing within the scope of the claims whichfollow.

What is claimed is as follows:

1. In a hydraulic cont-r01 system having a jet pipe with a nozzle at oneend thereof and including means for connecting pressure fluid theretoand means for shifting the pipe in opposite directions from a stationarynull position,

the combination of a receiver port member having a surface with tworeceiver ports opening thereto, said ports being independently connectedto oppositely disposed end chambers in which are respectively exposedpressure elfective opposed end surfaces of the receiver port member,

said chambers being adapted for connection to an output member,

said receiver port member, with the jet pipe in the null position andpressure fluid connected to the jet pipe, being shiftable in oppositedirections in response to a differential of pressure on the end surfacesof said member until the receiver ports are centered relative to the jetpipe nozzle at which time a pressure balance exists at the opposed endsof the member,

and means for locking said receiver port member in the centered positionrelative to the nozzle while said jet pipe is in the null position fornormal operation of said control system.

2. The hydraulic control system of claim 1 wherein the locking meanscomprises a locking screw, an end surface of which is adapted to engagethe receiver port member.

3. The hydraulic control system of claim 2 wherein the receiver portmember is provided with a jet pipe guide slot spaced from the receiverport surface and through which the jet nozzle end of the jet pipeextends,

said slot including opposed wall surfaces limiting movement of the jetpipe from the null position and preventing loss of communication of thenozzle with the receiver ports.

4. The hydraulic control system of claim 3 wherein the longitudinal axisof the guide slot is in the same plane as the common centerline of thereceiver port openings, and the slot width is suflicient to allow freemovement of the nozzle end of the jet pipe along the common axis of thereceiver port openings.

5. The hydraulic control system of claim 1 wherein the receiver portmember is provided with a jet pipe guide slot through which the nozzleend of the jet pipe extends and which is formed with oppositely disposedfixed end wall surfaces limiting movement of the jet pipe in oppositedirections from the null position and preventing loss of communicationof the nozzle with the jet receiver ports.

6. The hydraulic control system of claim 5 wherein a second slot isprovided in the receiver port member opposite the reeciver port surface,and the locking member comprises a screw member extending through thesecond slot and engaging a surface of the receiver port member opposedto the receiver port surface.

7. The hydraulic control system of claim 1 wherein the locking membercomprises a screw member engaging a surface of the receiver member onthe side of the receiver port member opposite to the receiver portsurface and also serving to prevent rotation of the receiver memberwhile being adjusted to the centered position.

8. An electro-hydraulic jet pipe control system comprisa housing havinga first bore perpendicular to and intersecting a second bore,

a jet pipe in the first lbore having a nozzle at one end and adapted tobe connected to a pressure fluid supply source,

means associated with the jet pipe responsive to an electric signal forshifting the pipe to opposite sides of a null position,

a receiver port member having opposed end surfaces shiftably mounted inthe second bore and forming chambers in said bore at opposite ends ofthe member adapted for connection to an output member,

said receiver port member having a surface between the end surfacesopposed to and spaced from the nozzle and with two closely spacedreceiver ports opening thereto,

said receiver ports being independently cross-connected to the endchambers of the receiver member.

said receiver port member with the jet pipe in the null position and apressure fluid supply source connected to the jet pipe beingself-adjustable in response to a differential of pressure in said endchambers for centering itself and the receiver port openings relative tothe nozzle, at which time a pressure balance exists in the end chambersand on the opposed end surfaces of said member,

means for locking said receiver member in said adjusted centeredposition relative to the nozzle for normal operation of the system,

and means for limting movement of said jet pipe on opposite sides of thenull position to prevent loss of communication of the nozzle with thereceiver ports.

9. An electro-hydraulic jet pipe control system as in claim 3 whereinthe receiver port member is provided with a slot opposed to the receiverport surface, and the locking means comprises a screw member threadableinto the housing having an end surface extending through said slot toprevent rotation of the receiver member and engaging said receiver portmember for locking the same in the centered position in said secondbore.

10. An electro-hydraulic jet pipe control system as in claim 9 whereinthe receiver port member is provided with a jet pipe guide slot spacedfrom and accurately located over the receiver ports, the nozzle end ofthe jet pipe extending through said jet pipe guide slot, and two opposedend surfaces of the jet pipe guide slot limiting movement of the jetpipe in opposite directions from the null position to prevent loss ofcommunication of the nozzle with the receiver ports, the longitudinalaxis of the jet pipe guide slot is in the same plane as the commoncenterline of the receiver port openings, and the jet pipe guide slotwidth is sufficient to allow free movement of the nozzle end of the jetpipe along the common axis of the receiver ports.

11. An eletcro-hydraulic jet pipe control system as in claim 8 whereinthe receiver port member is provided with a slot spaced from andaccurately located over the receiver ports, the nozzle end of the jetpipe extending through said slot, and two opposed end surfaces of theslot limiting movement of the jet pipe in opposite directions from thenull position to prevent loss of communication of the nozzle with thereceiver ports.

12. An electro-hydraulic jet pipe control system as in claim 11 whereinthe longitudinal axis of the slot is in the same plane as the commoncenterline of the receiver port openings, and the slot width issufiicient to allow free movement of the nozzle end of the jet pipealong the common axis of the receiver ports.

References Cited UNITED STATES PATENTS 2,601,207 6/1952 Jacques 13783 X3,205,782 9/1965 Fourtellotte 13783 X FOREIGN PATENTS 475,741 5/ 1929Germany.

ALAN COHAN, Primary Examiner.

1. IN A HYDRAULIC CONTROL SYSTEM HAVING A JET PIPE WITH A NOZZLE AT ONEEND THEREOF AND INCLUDING MEANS FOR CONNECTING PRESSURE FLUID THERETOAND MEANS FOR SHIFTING THE PIPE IN OPPOSITE DIRECTIONS FROM A STATIONARYNULL POSITION, THE COMBINATION OF A RECEIVER PORT MEMBER HAVING ASURFACE WITH TWO RECEIVER PORTS OPENING THERETO, SAID PORTS BEINGINDEPENDENTLY CONNECTED TO OPPOSITELY DISPOSED END CHAMBERS IN WHICH ARERESPECTIVELY EXPOSED PRESSURE EFFECTIVE OPPOSED END SURFACES OF THERECEIVER PORT MEMBER, SAID CHAMBERS BEING ADAPTED FOR CONNECTION TO ANOUTPUT MEMBER, SAID RECEIVER PORT MEMBER, WITH THE JET PIPE IN THE NULLPOSITION AND PRESSURE FLUID CONNECTED TO THE JET PIPE, BEING SHIFTABLEIN OPPOSITE DIRECTIONS IN RESPONSE TO A DIFFERENTIAL OF PRESSURE ON THEEND SURFACES OF SAID MEMBER UNTIL THE RECEIVER PORTS ARE CENTEREDRELETIVE TO THE JET PIPE NOZZLE AT WHICH TIME A PRESSURE BALANCE EXISTSAT THE OPPOSED ENDS OF THE MEMBER, AND MEANS FOR LOCKING SAID RECEIVERPORT MEMBER IN THE CENTERED POSITION RELATIVE TO THE NOZZLE WHILE SAIDJET PIPE IS IN THE NULL POSITION FOR NORMAL OPERATION OF SAID CONTROLSYSTEM.